This invention concerns punch holders for turret type punch presses, and more particularly multiple tool holders of a type described in U.S. Pat. No. 4,998,958.
U.S. Pat. No. 4,998,958 describes a punch tool holder carrying a number of punches, any one of which may be selected to be individually driven by the press ram.
It has also been heretofore known to mount individual punching tools to enable rotation to any of various desired orientations of the punching tool.
See U.S. Pat. No. 4,412,469 for an example of such a prior design.
U.S. Pat. No. 5,048,385 describes a tool holder capable of holding a number of punching tools any of which may be driven by the press ram.
In addition, the holder described therein is capable of positioning each tool at a desired orientation when engaged by the press ram. This is done by including a separately rotatable striker and tool carrier in the holder. The striker and tool carrier are rotated together to select a particular tool orientation and the striker separately rotated to select a particular tool.
This approach inherently requires sequentially staged rotation of the striker alone and the striker and carrier together, increasing the cycle time.
Furthermore, the tool holder is itself made more complicated by adding a striker to the holder in order to provide the variable tool orientation capability. Since many tool holders may be required to equip a turret type press, the increased costs of the more complicated holders can be significant.
Accordingly, an object of the present invention is to provide an arrangement for enabling a variable orientation of each tool in a multiple tool holder, which does not necessarily increase the cycle time or the complexity of the tool holder.
The multiple tool holders of the type shown in the above-referenced U.S. patents are typically installed in punch presses which already have indexing drives for rotating single punch holders to enable setting of various orientations of punches mounted in the press turret.
A disadvantage of multiple tool holders requiring rotation of the tool holder is that most older and some newer machines are not equipped with rotary indexing drives, which is impractical to add to existing machines.
Another object of the present invention is to provide a multiple tool holder and ram arrangement which does not require rotation of the tool holder to execute tool selection.